This new REN21 Renewables Global Futures Report presents views of 114 renowned energy experts from around the world, on the feasibility and challenges of achieving a 100% renewable energy future. Their thoughts are grouped into 12 Great Debates ranging from the future of heating and transport, the interconnection of sectors, the role of mega-cities and what utilities of the future could look like.

The report does not predict the future but should spur debate about the opportunities and challenges of a 100% renewable energy future.

The call for a 100% renewable energy future is gaining widespread support. It is a clear and simple concept, which expresses perfectly the ambition signaled by countries in signing of the 2015 landmark Paris Agreement. Holding global average temperature rise well below 2°C, not to mention a much safer limit of 1.5°C, requires nothing short of the complete decarbonisation of the energy sector. But the world is a complex place; what works in one country doesn’t necessarily work in another. Finding solutions for some sectors is easier than for others. The stakes are high – ?nancially, environmentally and socially – and as the transition progresses, there will be clear winners and losers.

This report follows on the tradition of the ?rst Renewables Global Futures Report (GFR) authored by

Dr. Eric Martinot, published in 2013. REN21 has canvassed a wide range of experts and stakeholders from around the world asking them about their views on the feasibility of achieving a 100% renewable energy future, and to explore what the related macro-economic impacts might be.

The GFR is not an advocacy report. The very fact that experts were included whose views run contrary to the 100% vision makes that clear from the outset. Rather, its aim is to present the complex and nuanced opinions and discussions of energy experts from all over the world. How feasible is the goal of reaching a 100% renewable energy future, and what is the likelihood of doing so by mid-century? What are the challenges that will need to be overcome to get us there? And who will bear the costs – either of action or inaction? This report, like its 2013 predecessor, represents a “mosaic” of insight into these questions – it does not present just one vision for the future.

By presenting the full spectrum of views, some might be tempted to conclude that getting to 100% renewables by mid-century is a pipe dream – but if we’ve learned one thing about renewable energy deployment over the last decades, it’s that with suf?cient political will – to adopt good policies and create ?nancial incentives – most obstacles can be overcome. This report therefore should not be seen as an attempt to predict the future, but to better understand and discuss the opportunities and challenges.

These are exciting times. Renewable energy technologies are coming of age, and are increasingly costcompetitive with conventional fuels. And given their vast global potential, they will become increasingly dominant in the years to come. They are no longer the “alternative” energy sources of the 1970s; they are the mainstream technologies of the 21st century.

Nonetheless, uncertainties about the pathway towards this future remain. The following section contains the most pressing subjects that need to be addressed in order to enable high-shares of renewables on a global level. These subjects are hotly contested by the energy experts interviewed for this report, coming as they do from different regions, from countries at different stages of development, and from different sectors within the energy ?eld. We refer to such conversations here as the “great debates.”